Surface grinder



Nov. 2, 1937.

, A. DE MARCHI ET A1.

SURFACE GRINDER Filed Jan. 1e, 1937 2 Sheets-Sheet l Nov. 2, 193;?. A.DE MARCHI ,ET AL 2,097,655

SURFACE GRINDER Filed Jan. 16, 1937 2 Sheets-Sheet 2 z rfc/ 17. Sano/fflPatented Nov. 2, 1937 UNITEr [STATES PATENT OF SURFACE GRINDER Artudo DeMarchi land David A. Sandin,

9 Claims. 'Ihis invention relates to surface `grinding machines such,for example, las used inflni'shing floors, walls, and the like .laid interrazzo or similar materials. Particularly the invention i provides animproved grinding machine `for simultaneously grinding, collecting andcarrying away the .dust produced in the 'grinding and finishing vactionin .the carrying Aout of .grinding or nishing under the dry process .as`distinguished from the wet process, where .Water is employed in theygrinding action.

Generally stated, the invention consists of the novel devices,combinations of devices, and arrangement of parts hereinafter described,and defined in the claims.

In a sense the `present invention is in the nature of an improvement4 onor a modification Or refinement of the device or machinedisclosed in theDe MarchiiPatent No; 1,936,449, issued of date November 21, 1933,1andentitled Terrazzo grinder". y

In the accompanying drawings, there is illustrated a commercial form ofthe rimprovedgrinder which embodies what is, at presentconsidered the'most Aapproved form ,or lembodiment of the invention. v l

Referring to the drawings, .whereinflike .,cha'ractersindicate likeparts 4throughout:the several views:

Fig. 1 is a side elevation, with some parts broken away, showing thecomplete grinding machine;

Fig. 2 is an enlarged view partly in side elevation, but partly invertical axial section, showing the grinding and suction head portionsof the improved machine, some parts being broken away; l Fig. 3 is asection taken on the line 3--3 of Eig.,2; and

Fig. 4 is a section taken on the line 4--4 of Fig. 2.

.1 The power device illustrated and preferably employed is an electricmotor,`the iixedvor body portion of which is indicated by the character5 and the rotor shaft thereof by the `character y6. This'motor may besupported in various ways'but preferably and, as shown, is mounted on atrucklike carrier 1, through the intervention of a turntable structure8. As a means-for transmitting power from the rotor of the motor to thegrinding tool or wheel, a flexible transmission shaft 9 iS connected tothe rotor 6 of the motor by a suitable coupling `such as that indicatedat Ill. At a point close to the coupling I the shaft 9 extends throughand is journaled in a non-rotary bearing II thatl isrigidly connectedtothe fixed part of vthe motor frame 5, by a yoke I2 or other suitablemeans.`

The extended portion of the exible shaft 9 is extended through andjournaled in a iiexible casing I3, one end of which is anchored to thefixed bearing il by a suitable coupling, such as that `indicated at lli.The flexible shaft 9 and fiexible vcasing I3 are of well-knowncommercial form, and'hence; the details thereof require no furtherexplanation. Thelength of the said elel0 ments 9 and i3 may varyto suitthe requirements of rany particular work. At its extended end the casingi3 is coupled to a bearing tube I5 which, by movements of the flexiblecasing, is made portable and capable of large range of shiftingmovement, not only with, but irrespective of movements of the motor. Inaccordance with this invention the connection between the free orextended end of the `casing I3 and the bearing tube I5is made asfollows: a metallic end tube 20 Iii is clinched or otherwise secured tothe end of ythe casing I3, and has screw-threaded engagement withanintermediate tubular coupling Il which, .in turn, has screw-threadedengagement ,with the `somewhat enlarged rear endof the bearing tube I5.

' "The grinding wheel or `tool shown is illustrated as and may beassumed to be a carborundum wheel I8 of drum-like form that isdetachably secured to a driving spindle I9. This grinding wheel, at oneend, has an enlarged recess 20 and in ,its .bore there is inserted ametallic bushing 2| which, in turn, is directly mounted on the somewhat.reduced outer Hendof the spindle I9. By means of a-nut 2,2 applied tothe outer end of ,35 the Vspindle I9, the inner end of grinding wheel I8will be tightly pressed Yagainst shoulder-forming, rib '23 ofthe'bushng, and the bushing will be pressed against a shoulderZfl 'ofthe spindlejIQ.

lThe spindlejlextends through and is jour- 40 naled within the bearingtube I5, by suitable means suchasball'bearings `25. The fixedelenrents'of the outer end of the Yball bearing devices 25 areldirectlyapplied in a collar 26 thatv is screwed onto theadjacentlend of thebearing tube I5. The fixed element of the inner end of ball bearingdevice 125 is `applied in the somewhat enlarged end of the bearing tube`I5 and is clamped'bet-ween the coupling element Il and the adjacentshoulder.o`f..said tube. AtLits inner end 50 the spindle "I9 `has vanoutstanding flange 2l against which the-rotaryielement of the inner endball bearing device 25 engages. Of course, the rotaryelementslofatheball `bearing devices 25 are rigidlyjappliedon the spindle I9 forrotation 55 therewith. The bearing tube I5 s intended to contain greaseor lubricant, and hence, its outer end is shown as closed against theleakage of grease, by a washer 23.

The extended end of the flexible shaft 9 is passed from the iiexiblecasing I3 proper into the end or terminal tube I6 of said casing, andits end is coupled to the wheel spindle I9 for rotation of the latterand of the grinding wheel, by means of a coupling in the form of a rigidmetallic terminal shaft 29. This shaft 29 is formed with a socket intowhich the end of the flexible shaft 9 is telescoped and there secured bya setscrew 39 or some other suitable means. The reduced end of the shaft29 is angular in cross-section and is telescoped into a correspondinglyformed axial seat of the spindle I9. In this way the iiexible shaft andwheel spindle I9 are connected for common rotation under powertransmitted from the motor, and wear or any slight axial movement of theconnected parts is compensated for by possible sliding movements of theshaft 29, in respect to the spindle I9.

As already indicated, means is provided for picking up the dust producedby the grinding wheel andconveying the same to a suitable point ofdischarge. 'As a most eflicient means for accomplishing this result,there is provided a suction fan mounted on the motor frame. This suctionfan may be of any approved or suitable type and, as shown, consists of afan casing 3l directly secured on top of the motor frame and providedVwith a discharge spout 32 that may lead tol any suitable point or placeof discharge, either at the exterior of the room or to a dust-collectingbag, such as frequently employed for similar purposes. The rotor shaft33 of this suction fan is shown as provided with a pulley 34, overwhich, and a pulley 35 on the motor shaft 6, runs a driving belt 36. Theaxial intake 31 of this fan is connected to a flexible air tube 38, theextended end of which is connected to a metallic suction tube 39.

This suction tube 39 extends parallel to the common axis of the elements|5--I9v and by a coupling, preferably in the form of a short tube 49, isspaced from but rigidly connected to a long sleeve 4I that is journaledon the bearing tube I5 and is held against axial movements between theend tube 26 and a shoulder of the tube I5. Adjustably mounted on thefront end of the suction tube 39 is a suction-acting nozzle 42, thesleeve-like upper portion of which quite closely fits the projecting endof the tube 39 and the depending portion of which is of segmental formand provided, at its extreme lower edge, with a long intake port 43 thatis adapted to be positioned close to' the floor and close to thegrinding surface of the wheel I 8. The suction nozzle 42, at its outerend, is entirely closed by an end wall and at its inner end, it isclosed, except for the passage that permits the same to be telescopedonto the tube 39. By reference to Fig. 3, it willV be noted that thetube 39 is provided with a segmental port 44 that opens the nozzlealways to the interior of the tube 39, irrespective of its variousadjustments.

By reference to Fig. 2, it will be noted that the distance between theparallel end portions of the slot 45 are spaced approximately thedistance represented by the length of the recess 2U in the outer end ofthe grinding wheel I8. In practice, it is found that the reduced outerend portion of the grinding wheel will sometimes be broken olf, therebyshortening up the grinding wheel to the extent represented by the depthof the recess 29. When the grinding wheel is complete, the adjustment ofthe nozzle 42 will be as shown in Fig. 2, but if the reduced end of thegrinding wheel be broken off, as above indicated, then the nozzle willbe slid toward the left, in respect to Fig. 2, to a position in whichthe screw 46 will be in the right-hand prong of the slot 45. It will befurther noted that when the nozzle is adjusted with the screw in eitherone of the prongs of the slot 45, the nozzle is capable of oscillatoryadjustments to properly position the same in respect to the grindingwheel.

The body of the tube 39 affords a handle that may be readily gripped byone of the hands of the operator, while the other hand is engaged withan extended handle piece 41 that is rigidly secured to' the tube 39 andradiates therefrom. When the device is thus held by the two hands, it isevident that the grinding wheel can be moved over the floor or othersurface, at Will, and by oscillatory movements, the nozzle can be heldin proper position, in respect to the floor or surface being ground.

Of course, the flexibility of the driving shaft and its casing permitthe grinding wheel to be moved over considerable surface withoutimparting movement to the motor and its truck. The motor and the truckare always free to follow the grinding wheel under pulling actionproduced through the flexible connections; and with the motor mounted ona wheel truck, the travelling movements of the latter are very easilyaccomplished. However, with the turn-table connection between the motorand the tru-ck, it is possible, without producing any turning movementsvof the truck itself, to cause the motor to follow the grinding wheel inmaking complete travelling movements of the grinding wheel around acircle; and from this point of view, the pivotal or turn-tableconnection between the truck and motor, and parts supported therewith,has, in practice, been found highly important.

The improved device is not only of simple construction, Vstrong anddurable, but is capable of the various required manipulations performedwith the greatest ease and work-producing accuracy, both on floors,walls, coves, cornices, ceilings and the like.

From the foregoing, it will be understood that the preferred form of thedevice illustrated in the ,drawings is capable of modication within thespirit of the invention herein disclosed and claimed.

In practice we have found that for some work it is highly desirable thatvery considerable pressure be produced on the grinding wheel. To provideconvenient device for manually accomplishingrthis pressure, there isprovided an auxiliary or additional handle 48fspaced from but locatedjust above the nozzle 42 and provided with a threaded stem 49 passedthrough a perforation in the hand piece 4l and provided with a nut 59.This auxiliary handle 48 may be applied, as shown in Fig. 2, it may bereversed and applied in the opposite direction over the body of thesuction tube 39, or it may be entirely removed.

It should be either removed or reversed, as in- 75 dicated, Whenever thegrinding Wheel has to be passed under an object that Would be engaged ifthe said hand piece 48 be applied, as shown in Fig. 2.

What is claimed is:

1. In a device of the kind described, a truck, a motor mounted on saidtruck for horizontal swivelling movements, an extended flexibletransmission shaft driven from said motor, a grinding Wheel connected toand driven from the extended end of said flexible shaft, a suction fanmounted on said motor for oscillatory movements therewith, means drivingthe rotor of said fan from the rotor of said motor, a suction tubeassociated with the extended end of said transmission shaft andconnected to the intake of said fan, by a flexible air tube, and anozzle head swivelled to the end of said suction tube and closelyassociated with said grinding wheel.

2. In a. device of the kind described, a rotary motor, a rotary suctionfan mounted on and driven from said motor, a flexible tubular casinganchored to and extended from the frame of said motor, a bearing tubeconnected to the extended end of said casing, a grinding Wheel having aspindle journaled in said bearing tube, a exible shaft extended throughsaid flexible casing and having one end connected to the rotor of saidmotor and its. extended end connected to the spindle of said grindingwheel, a sleeve mounted on said bearing tube for oscillatory movements,a suction tube extended parallel to but spaced from and rigidlyconnected to said sleeve, a flexible air tube connecting said suctiontube to the intake of sai-d fan, and a nozzle head applied tothe end ofsaid suction tube and closely associated with said grinding wheel, saidnozzle head being mounted on said suction tube for oscillatoryadjustments toward and from said grinding Wheel.

3. The structure defined in claim 2 in which said suction tube serves asone hand piece and is pro-vided with a radially extended arm thataffords another hand piece.

4. The structure dened in claim 2 in which said grinding wheel is ofdrum-like form having an enlarged recess at its outer end, and saidspindle is provided with a nut located within said recess, and in whichsaid nozzle head is mounted on said suction tube for oscillatory andaxial adjustments, said nozzle head having a sleeve-like portion formedwith a channel-shaped slot and said suction tube having a clamping boltWorking in said slot, the extremities of said slot being circumferentialof said tube and being spaced approximately the axial depth of theenlarged recess in the end of said grinding wheel.

5. The structure defined in claim 2 in which the suction tube isprovided with an auxiliary handle spaced from but applied over saidnozzle head.

6. The structure defined in claim 2 in which the suction tube isprovided with an upstanding handle and with an auxiliary hand pieceapplied to the latter in a position spaced above but overlying saidnozzle head.

7. The structure defined in claim 2 in which the suction tube isprovided with an upstanding handle and with an auxiliary hand pieceapplied to the latter in a position spaced above but overlying saidnozzle head, said auxiliary handle having a nut-equipped stern passedthrough a perforation in said upstanding handle and thereby maderemovable and reversible.

8. The structure dened in claim 2 in which said nozzle head is alsomounted for axial adjustments on said suction tube.

9. In a device of the kind described, a truck, an electric motor, theframe of which is mounted on said truck by a turn-table swivel, aflexible casing anchored to said motor frame and extended therefrom, atubular bearing anchored to the free end of said casing, a grindingwheel having a spindle journaled in said tubular bearing, a exibletransmission shaft extended through said iiexible casing with one endconnected to the rotor of said motor and with its other end connected tothe spindle of said grinding Wheel for rotating said grinding Wheel, infurther combination with a suction fan mounted on the frame of saidmotor, means for driving the rotor of said fan from the rotor of saidmotor, `a sleeve mounted on said bearing tube for oscillatory movements,a suction tube spaced from but rigidly connected to said sleeve, aflexible air tube connecting said suction tube to the intake di saidfan, and a nozzle head swivelled to the end of said suction tube andclosely associated with said grinding Wheel.

ARTUDO DE MARCHI, DAVID A. SANDIN.

